DRM is a finicky beast. Caught between trying to protect their bottom line against piracy and still provide something customers actually want to buy, developers have toyed with various models and methods of the stuff in their games. Products like StarForce generally receive a hiss from knowledgeable gamers everywhere; while later versions of the DRM software are not as bad as the older ones, StarForce used to install its own device driver on your computer which would run whether or not you were playing a game– invasive enough on its own, but said driver would remain installed even after the game was uninstalled. For reasons like that, as well as alleged instabilities caused by the driver, both Boing Boing and CNET went so far as to call the DRM method "malware."
SecuROM is similarly as ubiquitous, though significantly less invasive on your system. Typically it's used to tie a certain number of machines to an activation license, forbidding you from activating the game if you exceed that limit. The problem with this, however, is that activations typically aren't revoked if you uninstall the software, and there's usually nothing to be done if you simply reformat your computer– how many people really remember to go through and uninstall all of their games if they intend on wiping the harddrive entirely in the first place? As a "hardcore gamer" I tend to upgrade my equipment pretty regularly, and I suspect I'm on a list somewhere at Direct2Drive headquarters due to how often I have to email someone to reset my activations.
By and large my preferred method is Valve's Steam, which includes no further DRM on their own games (like Half Life 2 and Portal) aside from the connectivity of the service; games are tied to your Steam login ID and only one computer can be logged into Steam at a time. Publishers can choose to use only this or employ their own DRM in addition to Steam's, and companies like EA have waffled back and forth on whether or not they will accept Valve's implementation alone. As an additional plus, you can redownload games whenever you want and don't have to worry about losing a disc or .exe file.
Taking a page from this, though arguably going a step further, Ubisoft has stated with the release of upcoming title The Settlers 7, they will require online connectivity to activate and play their future games. Promising that the game won't have a set limit of activations (the direct quote from Brent Wilkinson, Director of Customer Service and Production Planning at Ubisoft, is, "If you own a hundred PCs, you can install your games on a hundred PCs.") and will allow gamers to sync their saved games onto the Ubisoft "cloud," letting them pick up from where they left off on any computer, the downside is that you will need constant connectivity to the internet to play your game.
While this is less of an issue today than it might have been five years ago, the problem isn't eradicated entirely; especially with the proliferation of laptops and netbooks, people aren't necessarily playing their games at home. An irritating issue I had with Fallout 3 was attempting to play on my laptop while on an transcontinental flight in 2008 from London to Sydney. Even though Steam has an offline mode and the Games for Windows Live also, theoretically, supports an offline profile, in practice without an internet connection in the middle of the air this was hit or miss. Sometimes I had access to my saved games, sometimes I did not. In the end I gave up entirely and ran through Warcraft 3's skirmish mode for several hours instead.
It remains to be seen how Ubisoft will deal with issues like this; the PC authentication will be added to existing Ubi.com accounts with the release of The Settlers 7 public beta on Monday, so we'll have a better idea of it in practice at that time. Obviously the preferred route would be no DRM at all, but if something has to be included I don't have any real objections to the Steam method. If Ubisoft manages to make sure gamers still have access to their saved games even without an internet connection then I think I can be okay with this too. But it's going to really suck if I am expected to have a perpetual internet connection 100% of the time I want to play one of their games. It's also a moot point when whatever DRM they come up with is cracked in a matter of days or hours anyway, reaffirming the reality that DRM only restricts legitimate customers and does nothing to protect your products from people who want it for free.
No sooner did I post this than did a FAQ appear on the Ubisoft site detailing further plans.
Unfortunately it seems to confirm some of my worst concerns with the announcement, namely that there will be no offline mode and you will require perpetual internet connectivity whether you're playing a single player title or not. It's also intended to be in all future Ubisoft titles.
Is there an "off-line" option?
No. The added services to the game (unlimited installs, online storage of saved games and the fact that you don't need the game disc to play) require you to have an online connection while playing the game.
Can I play from an airport or when I'm travelling?
Anywhere you have an internet access, you can play.
What will happen if I lose my Internet connection when I play the game?
If you lose your Internet connection the game will pause while it tries to reconnect. If the Internet Connection is unable to resume you can continue the game from where you left off or from the last saved game.